MX2011000465A - High temperature resistant insulation for pipe. - Google Patents

Abstract

A polymeric composition for insulating fluid and/or gas transport conduits, such as off-shore oil and gas pipelines operating at temperatures of 130°C or higher in water depths above 1,000 metres. The outer surface of the conduit is provided with at least one layer of solid or foam insulation comprising a high temperature resistant thermoplastic having low thermal conductivity, high thermal softening point, high compressive strength and high compressive creep resistance. The high temperature resistant thermoplastic is selected from one or more members of the group comprising: polycarbonate; polyphenylene oxide; polyphenylene oxide blended with polypropylene, polystyrene or polyamide; polycarbonate blended with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, or polyetherimide; polyamides, including polyamide 12 and 612 and elastomers thereof; polymethylpentene and blends thereof; cyclic olefin copolymers and blends thereof; and, partially crosslinked thermoplastic elastomers, also known as thermoplastic vulcanizates or dynamically vulcanized elastomers.

Description

ISOLATION RESISTANT TO HIGH TEMPERATURES FOR PIPING FIELD OF THE INVENTION The present invention relates to polymeric compositions for isolating transport conduits for liquids and / or gases, insulated transport conduits with these compositions and methods for the production and application thereof. More particularly, the polymeric compositions according to the invention comprise thermoplastics resistant to high temperatures having low thermal conductivity, high thermal softening point and high resistance to compression corrugation for use in the thermal insulation of liquid transport conduits and / or gases such as oil and gas pipes.

BACKGROUND OF THE INVENTION There is a growing demand in the oil and gas industry for superior performance thermal coatings to insulate and protect offshore transport pipelines operating at temperatures of 130 ° C or more, in water depths above 1,000 meters. In order to maintain the conduit and operating temperatures required at these depths, the coatings will have low thermal conductivity to avoid the formation of hydrates and waxes that can compromise the efficiency of the product.

Pumping of the fluid in the conduit. The thermal conductivity can also decrease through the foaming of the coating to some required degree. The materials used in this application should also exhibit a high softening point, high thermal stability and high drag to compression in order to withstand operating temperatures and hydrostatic pressures acting on the liner in deep water pipe installations. Without sufficient compressive strength, the insulation will be compressed in thickness, thus increasing the thermal conductivity and altering the dimensions and thermal performance to hydrodynamic of the system. Also, it is important that the coating remains sufficiently ductile after application to the conduit to prevent cracking during handling and installation of the pipe, for example, during winding on a barge and subsequent deployment thereof.

Multistage fluid flow is common in subsea fluid transport conduits, such as flow lines and elevators. Two major concerns in such systems are the formation of gas-water hydrates and the deposit of wax. Both phenomena refer to the fluid temperature and in extreme cases the conduit can be restricted or even severely blocked. This in turn can lead to reduced or lost production. In cases particularly serious, this may lead to the need to replace sections of pipeline or complete systems with corresponding loss of asset value. Thermal insulation is used to provide controlled energy loss of the system either in the idle condition or in the case of planned or unplanned interruption and therefore provide a reliable basis for operation.

For flow lines and elevators of a single pipe, using bonded external insulation, the mechanical loads as well as the requirements placed on the mechanical and thermal performance of the thermal insulation systems normally increase with the depth of the water. Therefore, the traditional thermal insulation foam technology used in shallow water and the associated design and test methodologies may not be applicable to deep water projects. In the case of long pipe tie-downs, for example, underwater moorings to the beach and in chaos where the service temperature is above about 150 ° C, there are limitations with current technology that can hide the successful development in oil fields or gas in deep water open sea.

Current technologies include unique pipe solutions, typically with insulation requirements in the heat transfer coefficient range of 3 - 5 W / m2K, using polypropylene foam or foam of polyurethane as the insulator and the so-called pipeline piping systems where a second pipe surrounds the primary conduit, the ring between the two pipes filling with insulating material.

The limitations and deficiencies of these technologies include: • Relatively high thermal conductivity of known insulation systems, which requires excessively thick coatings to achieve the required insulation performance, leading to potential difficulties in the foaming process, potential exhibits with residual stress, difficulties during pipeline deployment and bed instability Marine.

• Insufficient resistance to temperatures above 130 ° C, which result in compression and drag points in installations at high temperatures at high water depths.

• Excessive costs due to material costs versus performance capabilities or high transport and deployment costs.

• Disadvantages of deployment and operation with pipeline systems due to weight factors that lead to warping and welding failure if not solved properly and the need for high clamping loads during pipe laying.

Although the polystyrene-based insulation systems described in International Publication No. WO 2009/079784 A1 by Jackson et al. (Incorporated herein by reference in its entirety) provide improved thermal performance over known insulation systems at operating temperatures up to about 100. ° C, these polystyrene-based systems generally have insufficient resistance to temperatures above 130 ° C.

Therefore, there is a need for improved coatings for thermal insulation and protection of fluid and / or gas transport conduits such as oil and gas pipes, particularly those operating at high temperatures in excess of 130 ° C in water depths. above 1,000 meters.

SUMMARY OF THE INVENTION This invention overcomes the aforementioned deficiencies by the use of a thermoplastic solid or foam insulation having superior thermal and mechanical properties in relation to existing thermoplastic insulation materials to provide the thermal insulation required at the high temperatures and high hydrostatic pressures experienced in fluid and / or gas transport ducts located in deep water.

In one aspect, the present invention provides insulation and protective coatings comprising at least one thermal insulation layer of a thermoplastic resistant to high temperatures, containing gas bubbles and having the desired properties of low thermal conductivity, high thermal stateliness and high resistance to compression at high temperatures and pressures.

In another aspect, the present invention provides insulation and protective coatings comprising at least one thermal insulation layer of a thermoplastic resistant to high temperatures, containing hollow polymer, glass or ceramic microspheres and having the desired properties of low thermal conductivity. , high thermal stability and high resistance to compression at high temperatures and pressures.

In yet another aspect, the present invention provides insulating and protective coatings comprising at least one layer of thermal insulation of high-temperature, foam-free, solid-temperature thermoplastic having the desired properties of low thermal conductivity, high thermal stability and high strength. under compression at high temperatures and pressures.

In yet another aspect, the present invention provides insulating and protective coatings comprising at least one layer of high-resistant thermoplastic. foamed or unfoamed temperatures and at least one other layer of a different polymeric material, foamed or unfoamed having the desired properties of low thermal conductivity, high thermal stability and high compressive strength at high temperatures and pressures.

In still another aspect, the present invention provides insulating and protective coatings comprising at least one layer of thermoplastic resistant to high temperatures foamed or unfoamed and at least one other layer of polymer of the same composition or different foamed at the same or different degree or density and having the desired properties of low thermal conductivity, high thermal stability and high compressive strength at high temperatures and pressures.

In some other aspect, the present invention provides a method for manufacturing and applying said insulating and protective coatings whereby at least one layer of thermoplastic resistant to high temperatures is extruded, optionally foam and applied as a layer or layers of insulation thermal, to the outside of a steel tube.

In yet another aspect, the present invention provides an insulated fluid and / or gas transport conduit, such as a high temperature gas and oil pipeline for use in subsea environments, the pipeline comprising: (a) a continuous steel pipe consisting of one or more sections of tube, where the steel tube has an external surface and an internal surface; (b) a corrosion protection system comprising a high temperature corrosion protection coating attached directly to the surface of the steel tube and the adhesive or final layer as required; and (c) at least one layer of thermal insulation applied to the corrosion protection system, wherein at least one layer of the thermal insulation is comprised of a thermoplastic resistant to high temperature, which has low thermal conductivity, high point of softening, high thermal stability, high compressive strength and high resistance to compression drag and that is optionally foamed.

In a further aspect, the present invention provides a system for protection and insulation of a thermoplastic tube, comprised of a thermoplastic resistant to high temperatures, compatible with, and capable of being attached to, the above-mentioned insulating and protective coatings comprising at least less a thermoplastic layer resistant to high temperatures.

In a further aspect, the present invention provides insulated high temperature transport conduit for use in offshore, deep water environments, the conduit comprising: (a) a continuous steel tube formed of one or more pipe sections, wherein the steel tube has an external surface and an internal surface; and (b) a first thermal insulation layer provided on the external surface of the steel tube, wherein the first thermal insulation layer is comprised of a thermoplastic resistant to high temperatures having low thermal conductivity, high point of thermal smoothing, high Compression resistance and high resistance to compression drag.

In a further aspect of the present invention, the first thermal insulation layer may be solid, or it may be a blowing foam or syntactic foam having a foam phonation degree of up to about 50%. The degree of foaming of the first thermal insulation layer may be 5-30% or 10-25%.

In a further aspect of the present invention, the first thermal insulation layer has one or more of the following properties: high compressive drag at high temperatures (< 7% triaxial); high compression module (> 1000 MPa); high compressive strength (> 25 MPa, uniaxial); low thermal conductivity (<0.200 W / mK); high capacity to support long-term tempers (> 130 ° C). The first layer of thermal insulation can have all these properties.

In a further aspect of the present invention, high-resistant thermoplastic is selected temperatures of one or more members of the group comprising: polycarbonate; polyphenylene oxide; polyphenylene oxide mixed with polypropylene, polystyrene or polyamide; polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, or polyetherimide; polyamides, including polyamide 12 and 612 and elastomers thereof; polymethylpentene and mixtures of the earthquake; cyclic olefin copolymers and mixtures thereof; and, partially entangled thermoplastic elastomers, also known as thermoplastic vulcanizers or dynamically vulcanized elastomers.

In a further aspect of the present invention, the thermoplastic resistant to high temperatures is selected from the uro comprising polyphenylene oxide and polyphenylene oxide mixed with polypropylene, polystyrene or polyamide.

In a further aspect of the present invention, the high temperature resistant thermoplastic is selected from the group comprising blends of polyphenylene oxide with polystyrene and polyphenylene-polypropylene oxide.

In a further aspect of the present invention, the high temperature resistant thermoplastic is selected from the group comprising polycarbonate and polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate or polyetherimide.

In a further aspect of the present invention, the thermoplastic resistant to high temperatures has a Vicat smoothing point on the scale of 130-200 ° C and a thermal conductivity of 0.15-0.20 W / mK.

In a further aspect of the present invention, the insulated high temperature transport duct further comprises a corrosion protection coating directly applied to the outer surface of the steel tube and attached thereto and underlying the first thermal insulation layer.

In a further aspect of the present invention, the corrosion protection coating comprises a cured epoxy or modified epoxy layer. The corrosion protection coating may comprise an epoxy phenolic, polyphenylene sulfide, polyphenylene oxide or polyimide, including modified versions and mixtures thereof.

In a further aspect of the present invention, the first thermal insulation layer is in direct contact with the corrosion protection coating and directly adhered to it, the corrosion protection coating that has been treated by plasma or Corona discharge before application of the first thermal insulation layer.

In a further aspect of the present invention, the corrosion protection coating comprises a multi-layer corrosion protection system applied to the outer surface of the steel tube and underlying the first thermal insulation layer, wherein the system of multi-layer corrosion protection applied to the outer surface of the steel tube and underlying the first thermal insulation layer, wherein the multi-layer corrosion protection system comprises: (a) a layer of the cured epoxy or modified epoxy applied directly to the outer surface of the steel turbo and attached thereto; and (b) a first layer of adhesive applied directly to the corrosion protection layer and underlying the first layer of thermal insulation. The adhesive layer can be comprised of a polymer with functional groups and having a mutual affinity for the corrosion protection layer and the first thermal insulation layer. The first layer of thermal insulation is in direct contact with the first layer of adhesive and is bonded thereto.

In a further aspect of the present invention, the multilayer corrosion protection system further comprises: (c) a first top cover protective layer comprised of an unfoamed polymeric material in direct contact with the first adhesive layer and bonded thereto, wherein the first thermal insulation layer is in direct contact with the first protective top cover and bonded thereto.

In a further aspect of the present invention, the corrosion protection coating comprises a single mixed layer corrosion protection coating applied to the outer surface of the steel tube and attached thereto and in direct contact with the first thermal insulation layer, wherein the single-layer mixed corrosion protection coating comprises a cured epoxy resin, an adhesive and a non-foamed polymeric material.

In a further aspect of the present invention, the insulated transport duct further comprises an outer protective top cover applied to the first thermal insulation layer and forming an external surface of the insulated transport duct, wherein the external protective cover is comprised of a non-foamed polymeric material.

In a further aspect of the present invention, the upper insulation cover is in direct contact with the first protective cover and directly adhered to it, the first thermal insulation layer that has been treated by plasma or corona discharge before application to the first external protective cover.

In a further aspect of the present invention, the insulated transport conduit comprises a second thermal insulation layer in the form of a solid, a blowing foam or a syntactic foam. The second thermal insulation layer may be comprised of a polymeric material that is different from the high temperature resistant thermoplastic comprising the first thermal insulation layer. The different polymeric material may be selected from one or more members of the group comprising: homopolymer or copolymer of solid or foamed polypropylene, polybutylene, polyethylene; polystyrene, high impact polystyrene, modified polystyrene and polypropylene and interlaced or partially interlaced polyethylenes, including copolymers, blends and elastomers thereof; and the first thermal insulation layer underlying the second thermal insulation layer. The first and second thermal insulation layers can be foamed to a greater degree than the first thermal insulation layer.

In a further aspect of the present invention, the first thermal insulation layer is under the second thermal insulation layer and is in direct contact with the second thermal insulation layer and directly adhered to it, the first thermal insulation layer having been treated by plasma discharge or corona before the application of the second layer of thermal insulation.

In a further aspect of the present invention, the first and second thermal insulation layers are separated by a layer of non-foamed polymeric material.

In a further aspect of the present invention, inter-layer adhesion is provided between the unfoamed polymeric material layer and the first and second thermal insulation layers by treating the first thermal insulation layer with plasma discharge or coane before the application of the layer of unfoamed polymeric material and by plasma or corona discharge of the non-foamed polymeric material layer before the application of the second thermal insulation layer.

In a further aspect of the present invention, an adhesive layer is provided between the layer of unfoamed polymeric material and one or both of the first and second thermal insulation layers.

In a further aspect of the present invention, the insulated transport conduit further comprises a molded tube gasket insulation system attached directly to the corrosion protection coating system and first thermal insulation layer in a gasket connecting two sections of tube. The joint insulation system of the molded tube can be comprised of a thermoplastic resistant to high temperatures as defined herein.

In a further aspect, the present invention provides an insulated high temperature transport conduit for use in deep water open water environments, the conduit comprising: (a) a continuous steel tube formed of one or more sections of pipe, in where the steel tube has an external surface and an internal surface; and (b) a first thermal insulation layer provided on the outer surface of the steel tube, wherein the first thermal insulation layer is a solid, a blown foam or a syntactic foam and is comprised of polypropylene; and (c) a second thermal insulation layer provided on the first thermal insulation layer, wherein the second thermal insulation layer is a solid, a blowing foam or a syntactic foam and is comprised of polybutylene. Both the first and second layers of insulation can be a solid.

In a further aspect of the present invention, the corrosion protection coating comprises a single layer corrosion protection coating directly applied to the outer surface of the steel tube and is bonded thereto, wherein the protective coating the mixed corrosion of a single layer is comprised of a styrene-maleic anhydride copolymers.

The styrene-maleic anhydride copolymer can be mixed with acrylonitrile-butadiene-styrene (ABS).

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-section of an isolated pipe according to a first embodiment of the invention; Figure 2 is a cross section of an insulated pipe according to a second embodiment of the invention; Figure 3 is a cross-section of an insulated pipe according to a third embodiment of the invention; Figure 4 is a cross-section of an insulated pipe according to a fourth embodiment of the invention; Figure 5 is a cross-section of an insulated pipe according to a fifth embodiment of the invention; Figure 6 is a cross-section of an isolated pipe according to a sixth embodiment of the invention; Figure 7 is a cross-section of an insulated pipe according to a seventh embodiment of the invention; Y Figure 8 is a cross section of an insulated pipe according to an eighth embodiment of the invention.

Figure 9 is a cross section of an insulated pipe according to an eighth embodiment of the invention.

Figure 10 is a longitudinal cross section of the pipe joint area of 2 insulated pipes welded together.

DETAILED DESCRIPTION OF PREFERRED MODALITIES The present invention relates to insulating and protective coatings and conduits for transporting fluid and / or thermally insulated gas that incorporate said coatings for use in subsea environments. The present invention also relates to methods of manufacturing the insulating and protective coatings and for manufacturing highly insulated high temperature fluid and / or gas transport conduits incorporating the coatings.

The term "high temperature" as used herein refers to operating temperatures and / or service temperatures that are greater than 130 ° C, for example in the 130-200 ° C stand, or in the 150-200 ° C scale.

The term "solid" as used herein with reference to one or more of the layers of an insulated transport conduit means that the layers are defoamed, ie, solid layers as defined herein have a degree of foaming of 0% and do not incorporate microspheres as it may be present in syntactic foams.

The term "foam" as used herein includes blowing foams and syntactic foams, as defined in the following description.

The fluid and / or gas transport conduits described below are oil and gas pipes which are normally formed of one or more sections of steel pipes. The term "fluid and / or gas transport conduits" and similar terms as used herein, are meant to include said oil and gas pipelines and related components, including flow lines, elevators, bridges, reels, manifolds and auxiliary equipment.

A major consideration in the use of steel tubing is long-term corrosion tube protection under wet and high temperature service conditions. Therefore, the insulating and protective coatings according to the invention may comprise one or more layers of corrosion protection or a protection system for the corrosion of multiple layers that are applied to the steel tube jet treated and cleaned before the application of any subsequent layer, including at least one layer of thermoplastic resistant to high temperatures according to the invention. For example, the corrosion protection layer may comprise a cured epoxy layer applied directly to the outer surface of the steel tube and attached thereto.

It will be appreciated that the layers forming the insulating and protective coatings described below are not shown to scale in the drawings. In particular, the thicknesses of the layers making up the coatings are exaggerated in relation to the thicknesses of the other layers and also in relation to the thickness and diameter of the steel tube.

Figure 1 illustrates a cross section of an insulated oil and gas pipe 10 according to a first embodiment of the invention. The insulated pipe 10 includes one or more sections of the steel pipe 1 in which the insulating and protective coating includes a three layer corrosion protection system. According to this system, the steel tube 1 is coated with a corrosion protection layer 2 comprised of cured epoxy or other corrosion protection material at high temperatures as described below, a first layer intermediate adhesive 3 applied on the corrosion protection layer 2 and a first protective top cover 4 applied on the first adhesive layer 3. The first protective top cover 4 provides corrosion protection and added mechanics and the adhesive layer 3 provides a bond adhesive between the top cover 4 and the underlying corrosion protection layer 2. The top cover 4 is shown in Figure 1 as a relatively thin layer between the adhesive layer 3 and the upper insulation layers described below. The composition and thickness of the top cover 4 at least will partially depend on the compositions of the underlying adhesive layer 3 and the cover insulation layers, particularly with respect to adhesion to the layers. The top cover 4 may also comprise the first insulation layer. In terms of composition, the top cover may preferably comprise an extrudable thermoplastic resin which may comprise the same material as the roof thermal insulation layer, or a material compatible with or connectable to the thermal insulation layer, including a mixture of two or more ^ materials.

Figure 2 illustrates a cross section of an insulated oil and gas pipe 12 according to a second embodiment of the invention. The insulated pipe 12 includes one or more sections of the steel pipe 1 provided with a two-layer corrosion protection system, wherein the steel tube 1 is provided with a corrosion protection layer 2 comprised of cured epoxy or other corrosion protection material at high temperatures as described below and a first adhesive layer 3 applied on the layer 2, as in Figure 1. In the corrosion protection system shown in Figure 2, the first adhesive layer 3 is duplicated as an adhesive and top cover, thus eliminating the need for separate application of a first protective top cover 4. A similar two-layer corrosion protection system is shown in Figure 4 which illustrates a cross-section of an insulated oil and gas pipe 16 according to a fourth embodiment of the invention. invention.

As an alternative to the multilayer corrosion protection systems illustrated in Figures 1, 2 and 4, the steel pipe 1 may be provided with a single-layer mixed corrosion protection layer wherein the epoxy or other corrosion protection material at high temperatures described below, adhesive and polymer top cover components are pre-mixed and applied onto the tube 1 as a variable graduated coating. Figure 3 illustrates a cross section of an insulated oil and gas pipe 14 according to a third embodiment of the invention. The isolated pipe 14 includes one or more sections of the steel tube 1 provided with only a single-layer mixed corrosion protection coating 22.

In the isolated oil and gas pipes according to the invention, the insulation and protective coatings also comprise one or more thermal insulation layers, including one or more foamed layers and / or one or more non-foamed solid layers. The pipes 10, 12 and 14 illustrated in Figures 1 to 3 include a single layer of thermal insulation 6, while the pipe 16 of Figure 4 is provided with the first (internal) and second (external) thermal insulation layers 6. and 8. It will also be appreciated that the insulated oil and gas pipes according to the invention may comprise more than two layers of thermal insulation, each of which may be foamed or non-foamed.

When the insulated pipe includes a single layer of corrosion protection or a multilayer corrosion protection system, the thermal insulation layer 6 should adhere firmly to the corrosion protection layer or system. This is a particularly important consideration if the thermal insulation layer 6 and the underlying corrosion protection layer, or system, are comprised of different polymeric materials. The adhesion between the layers, also known as adhesion between layers, it also depends on the coating temperature and the application method of the layers. For example, it may be necessary to preheat the corrosion protection layer or system prior to the application of the upper thermal insulation layer 6 to better fuse the two layers and increase inter-layer adhesion. It may also be necessary to apply a layer of adhesive between the corrosion protection layer, or system and the thermal insulation layer 6. This is illustrated, for example, in Figure 1, in which a second adhesive layer 5 is applied. between the thermal insulation layer 6 and the underlying protective upper cover 4 of the three-layer corrosion protection system and serves to join the thermal insulation layer 6 to the upper cover 4. In the embodiments of Figures 2 and 4, the first adhesive layer 3 serves as an adhesive and a protective cover and joins the thermal insulation layer 6 with the corrosion protection layer 2. In the embodiment of Figure 3, the thermal insulation layer 6 is bonded directly to the layer corrosion protection 2 without the help of an adhesive layer.

Adhesion between layers can also be achieved by activating one or more of the surfaces that will be adhered using plasma or corona discharge treatment. In this case, a separate adhesive layer may be unnecessary.

If the thermal insulation layers 6, 8 are foamed, an additional consideration is the effect of interlayer adhesion on the integrity of the foam, since any collapse of the foam structure at the interface due to the heat and pressure applied to effect the adhesion will compromise the overall thermal insulation performance of the system.

As shown in Figures 1 to 5, an outer protective cover 7 can be applied over the outer insulation layer to give additional resistance to the static pressure at great depths, particularly if the outer insulation layer is foamed. The outer protective top cover 7 may, for example, comprise the same polymeric material as one or more of the thermal insulation layers, or a modified or reinforced version thereof, but preferably in a solid non-foamed state.

It will be appreciated that the outer protective top cover and thermal insulation layers may be comprised in their place of different polymeric materials, in which case it may be preferred to provide an additional layer of adhesive (not shown) between the outer thermal insulation layer and the outer layer. external protective It will also be appreciated that the protective cover 7 is not necessary in all embodiments of the invention and Figures 6 to 9 illustrate insulated pipes 18, 20, 24 and 26 which are identical to pipes 10, 12, 14 and 16, respectively, with the exception that they do not include a protective top cover 7. It will be appreciated that the outer protective top cover may be unnecessary , for example, wherein the external thermal insulation layer is a solid, or is foamed but naturally forms a solid membrane.

As shown in Figure 4, the insulating and protective coating may comprise more than one thermal insulation layer of the same polymeric composition foamed to different grades, or densities, or may comprise more than one layer of thermal insulation of solid or foam made of different polymeric materials. This allows the system to be tailored for precise thermal insulation performance related to the system requirements of the installed application.

The embodiment illustrated in Figure 4 includes an internal thermal insulation layer 6 and an external thermal insulation layer 8 which may have the same or different composition and / or density. The thermal insulation layers 6 and 8 are separated by a layer 9 of non-foamed polymer material which may have a composition equal to or different from one or both of the layers 6 and 8 and may function as an adhesive between the layers 6 and 8. It will be appreciated that an adhesive layer can be provided between layers 6 and 8 or between one or more layers 6, 8 and the adjacent non-foamed layer 9, or between any additional thermal insulation layer, particularly if the layers have a different composition. It will also be appreciated that the non-foamed layer 9 may not be necessary in all situations, for example, when the individual thermal smoothing layers can be directly bonded to each other or where the plasma or corona treatment is used to effect adhesion . This is illustrated in Figure 5 which shows an insulated pipe 17 identical to pipe 16 of Figure 4 except for the omission of the non-foamed layer 9 between layers 6 and 8.

Although the embodiments of the invention shown in the drawings include one or more layers of thermal insulation, it will be appreciated that the insulated pipes according to the invention may include more than two layers of foamed or unfoamed thermal insulation with or without non-polymer layers. foamed and / or adhesive being provided between the foam layers.

It is also necessary in the application to provide thermal insulation around the joint area where two lengths of zero pipe are welded. The composition of this pipe joint insulation system shall be attached to the corrosion protection layer, or system, applied directly over the welded pipe and layer joint, or layers, of existing thermal insulation, including any protective top cover and any other layers of the exposed insulated pipe as a result of the insulation cut off the ends of the pipe to allow welding them.

Figure 10 illustrates a longitudinal cross-section of a joint weld area of the circular pipe 11 in which two steel pipes 1 are joined. The steel pipes 1 each have an insulating and protective coating as shown in Figure 3 comprising a corrosion protection layer 22, a term insulation layer 6 and an outer protective top cover 7. However, it will be appreciated that the tubes 1 may be provided with any insulating and protective coating shown in the drawings or described herein. The welded area of the tube junction 11 is provided with insulation from the pipe joint 13 which, for example, is attached to a corrosion protection system 15 comprising an epoxy inner layer and an adhesive top layer and to the insulation 6 and top cover 7. The corrosion protection system 15 may have the same composition and thickness as any corrosion protection layer or systems described herein and the pipe joint insulation layer 13 may have the same composition than any thermal insulation layer described in the present. The joint isolation system is described below.

Layer Composition Corrosion Protection Coatings As mentioned above, it is advantageous to apply one or more layers of corrosion protection or a multilayer corrosion protection system to the steel tube before any subsequent layer. The initial corrosion protection layer, namely the coating directly bonded to the steel tube, may preferably be comprised of cured epoxy, or modified epoxy, which is applied to the cleaned or preheated tube surface either, a) as a melt-bonded powder by spraying the tube with powder spray guns, passing the tube through a "curtain" of powder or using a fluidized bed containing the powder, or, b) as a liquid coating using liquid spray guns. Epoxy curing results from contact with the hot tube.

It may also be preferred to apply additional coats over the partially cured epoxy. In the 3-layer corrosion protection system illustrated in Figure 1, an olefin-based adhesive copolymers, for example, a maleic anhydride-functionalized polyolefin, can be applied directly to the partially cured epoxy, followed by the application of a polymeric top cover on the adhesive for mechanical protection. The function of the adhesive is to join the top cover or the first layer of thermal insulation to the epoxy corrosion protection layer. The adhesive and polymer top cover can be applied by extrusion side wrapping or by powder spray methods.

The adhesive layer may also comprise a coextruded structure of two or more layers, the outer layers of which are attached to the respective corrosion protection layer and subsequent top cover or thermal insulation layer with which they are compatible.

As alternatives, the cured epoxies mentioned above, the corrosion protection layer may instead comprise modified epoxies, epoxy phenols, styrene-maleic anhydride copolymers such as mixtures of styrene-maleic anhydride-ABS (acrylonitrile-butadiene-styrene), polyphenylene sulfides, polyphenylene oxides, or polyimides, including modified versions and mixtures thereof. In some cases, it has been found that an adhesive layer is not necessary to bond these corrosion protection coatings to the pipe or to the top cover or first insulation layer. Some of these materials can also be used at higher service temperatures than the epoxy-based corrosion protection systems described above.

Some of the higher temperature resistant corrosion protection coatings mentioned above may also have properties that make them suitable for use as thermal insulation layers in any of the embodiments of the invention. While the corrosion protection coating will normally be comprised of a different polymer grade having different properties, it can be conceived that the same type and grade of the polymer can be used for protection against corrosion and thermal insulation. In this case, a single layer of this polymer can serve as a corrosion protection coating and thermal insulation layer.

An adhesive layer may not be necessary when it is possible to achieve bonding of adjacent layers using plasma or corona treatment.

Additional Adhesive Layer In cases where it is necessary to apply a layer of adhesive between the adjacent thermal insulation layers or between a thermal insulation layer and one or more of the other layers, including any solid protective layer and upper covers, particularly layers of different composition, the material used adhesive should join ideally in the same good way as the layers. The adhesives normally used are polymers with functionalities that have mutual affinity for the layers that require binding, the functionalities being specific to the chemical composition of the layers that require binding. Preferably the bond strength should be high enough to promote cohesive failure between the individual layers.

The adhesive layer may also comprise a co-extruded structure of one or more layers of the outer layers of which will be bonded to the respective insulation layers or top covers with which they are compatible.

The adhesive layer adjacent to the adjacent thermal insulation layers and between a thermal insulation layer and one or more of the layers may, for example, comprise a grafted polymer or copolymer, or mixture of polymers with one or more portions compatible with each one of the individual layers that will be joined.

The adhesive layer is preferably applied by application of powder spraying, or side wrapping, cross extrusion or co-extrusion methods.

A layer of additional adhesive may not be necessary where two adjacent layers have an affinity mutual between them, or where it is possible to achieve the anointing of the layers using plasma or corona treatment.

Layers of Thermal Insulation and Top Cover Protective The thermal insulators used in the present invention are designed to withstand operating temperatures in excess of the maximum operating temperatures (130 ° C) of systems currently used for the thermal insulation of subsea pipelines, such as polypropylene. These operating temperatures can be as high as 200 ° C. The thermal insulators are also designed to exhibit adequate compression drag and modulus at these temperatures to prevent the collapse of the foam structure in deep water insulators and therefore maintain the thermal insulation required during the life of the project. oil and gas recovery. In addition, the compositions may be sufficiently ductile to withstand the bending stresses experienced by the insulated pipe during winding and installation operations.

The insulating and protective coatings according to the present invention are prepared from thermoplastics resistant to selected high temperatures to provide solid or foam insulation layers with one or more of the following properties. • high resistance to dragging insulation at higher temperatures (<7% triaxial drag), • high compression module ((> 1000 MPa), • High compressive strength 8 > 25 MPa, uniaxial), • low thermal conductivity (<0.200 W / mK), • high specific heat capacity (> 1300 J / kgK), • ability to withstand high temperatures in the long term (> 130 ° C, eg, 130-200 ° C or 150-200 ° C), • adequate ductility (> 10% elongation at break).

The insulation layers according to the invention, having one or more of the above properties, are applied to sufficient thicknesses so as to provide the insulated transport conduit with an acceptable heat transfer coefficient (U) for the conditions under which they will be used, with U being normally on the scale of approximately 2 to around 10 / m2K. The thicknesses of the insulation layers are highly variable, due to the fact that each pipe system is designed to be used under specific conditions of depth, temperature, etc.

Preferably, the insulation and protective coatings according to the invention have all the above properties.

Thermoplastics resistant to high temperatures are preferably selected from one or more members of the group comprising: • polyphenylene oxide, • polyphenylene oxide mixed with homopolymers or copolymers of polypropylene, polystyrene and / or polyamide, • polycarbonate, • polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate and / or polyetherimide, • polyamides, such as polyamide 12 and 612 and elastomers thereof.

• Polymethylpentene and its mixtures. • cyclic olefin copolymers and their mixtures, • partially interlaced thermoplastic elastomers, also known as thermoplastic vulcanizates or dynamically vulcanized elastomers.

The intrinsic material properties of the above thermoplastics are noted below in Table 1.

Table 1 PPO-PS = polyphenylene oxide mixed with polystyrene PPO-PP = polyphenylene oxide mixed with polypropylene PC = polycarbonate PC-ASA = polycarbonate mixed with acrylonitrile styrene acrylate PA 612 = polyamide 612 PMP = polymethylpentene COC = cyclic olefin copolymer TPV = vulcanized thermoplastic The high temperature resistant thermoplastics for use in the present invention may have a Vicat softening point on the scale of 130-200 ° C, for example on the scale of 135-180 ° C; thermal conductivity not greater than 0.22, for example 0.15-0.20.

Where the thermoplastic resistant to high temperatures is polyphenylene oxide mixed with homopolymers or copolymers of polypropylene, polystyrene and / or polyamide, it will be understood that the mixture is comprised predominantly of polyphenylene oxide, that is, the polyphenylene oxide is present in the mixing in an amount of at least 50 weight percent. Examples of polyphenylene-polypropylene oxide blends useful in the present invention are commercially available under the tradename Noryl ™.

Similarly, where the high temperature resistant thermoplastic is a blend of any of the other high temperature resistant thermoplastics mentioned above (ie, polycarbonate, polyamide, or partially entangled thermoplastic elastomer), it will be understood that the blend is comprised predominantly of the thermoplastic. resistant to high temperatures, that is, so that the thermoplastic resistant to high temperatures is present in the mixture in an amount of at least 50 weight percent.

As mentioned above, one or more thermal insulation layer may be provided with an additional protective layer, or top cover, such as layers 7 and 9 described above, comprised of unfoamed polymeric material. Normally, but not necessarily, layers Protective devices are prepared from the same material as the underlying thermal insulation layer, or a modified or reinforced version thereof.

It may be required, for example, to impart a higher degree of physical or chemical performance, such as resistance to impact, abrasion, rupture or moisture, to the surface of the insulated tube, in which case it may be advantageous to prepare an external protective top cover of a material polymeric that has impact, abrasion, rupture or chemical resistance superior to that of which the layer or layers of thermal insulation is made. Said material may comprise the thermal insulation material mixed with suitable polymeric modifiers, compatibilizers, or fillers or reinforcing fibers, or may comprise a polymeric material, preferably compatible, different. In the latter case, it may be necessary to apply a layer of additional adhesive between the thermal insulation layer and top cover to effect the proper bonding of the two layers.

Also, as mentioned before, the insulation layers may comprise different materials, or foamed materials to different degrees. In a preferred example, a polymer with high temperature resistance or softening point so that the modified polyphenylene oxide can be used as an internal non-foamed or foamed thermal insulation layer closest to the steel tube hot to function as a heat barrier, with a non-foamed or foamed polymer resistant to lower temperature or lower thermal conductivity as a thermal, external, secondary, or tertiary insulation layer. Said outer layers may comprise polystyrene and modified polystyrene, including polystyrene and high impact styrene copolymers; polybutylene; homopolymer and polypropylene copolymers; polyethylene; and interlaced or partially entangled polypropylene and polyethylene, including copolymers, blends and elastomers thereof. It may also be necessary to apply a layer of additional adhesive between the layers of different insulation materials to effect proper bonding of the insulation layers.

The thermal insulation layers can also be foamed to different degrees the further away from the tube wall; for example, the outer layers of insulation can be foamed to progressively higher degrees than the inner layers to provide ready-made thermal performance of the system.

The thermal insulation compositions prepared from these materials may also contain additives selected from one or more members of the group comprising inorganic fillers, fillers or reinforcing fibers, nano fillers, conductive fillers, flame retardant fillers.

Flame, antioxidant, heat stabilizers, processing aids, comaptibilizers and pigments.

Foaming Agents The foamed thermal insulation layers in the insulating and protective coatings according to the invention can be prepared from the thermoplastics resistant to high temperatures mentioned above, incorporating chemical foaming agents, by physical injection of gas or volatile liquid, or by mixing with hollow polymer, glass or ceramic microspheres. Foams generated through the action of chemical or physical foaming agents are generally referred to as "blowing" foams. The foams containing hollow microspheres are referred to as "syntactic" foams.

Syntactic foams provide superior drag and break compression than blowing foams, but are generally less efficient heat insulators and are considerably more expensive. An optimized design of cost and performance, for example, may comprise one or more layers of syntactic foam surrounded by one or more layers of blowing foam insulation.

Chemical foam forming agents can function via an endothermic reaction mechanism (heat absorption) or exothermic reaction (heat generation). They are selected of one or more members of the group comprising sodium bicarbonate, citric acid, tartaric acid, azodicarbonamide, hydrazide 4,4-oxybis (sulfonyl benzene), 5-phenyl tetrazole, dinitrosopentamethylene tetramine, p-toluene sulfonyl semicarbazine, or mixtures thereof. Preferably the chemical foaming agent is an endothermic foaming agent, such as sodium bicarbonate mixed with citric or tartaric acid.

Chemical foam formation occurs when the foaming agent generates a gas, usually C02 or N2, through decomposition when heated to a specific decomposition temperature. The initial decomposition temperature together with gas volume, release rate and solubility are important parameters when choosing a chemical foaming agent and need to be carefully matched to the melting process temperature of the particular thermoplastic that is being formed.

For physical foam formation, the gas or volatile liquid used is selected from the group comprising C02, supercritical CO2, N2, air, helium, argon, aliphatic hydrocarbons, such as butanes, pentanes, hexanes and heptanes, chlorinated hydrocarbons, such as dichloromethane and trichloromethylene and hydrochlorofluorocarbons, such as dichlorotrifluoroethane. In the chaos of volatile liquids, foam formation occurs when the heated liquid is vaporizes in gas. Preferably the physical foam forming agent is supercritical CO2.

The hollow microspheres are selected from one or more members of the group comprising glass, polymer, or ceramic spheres, including silica and alumina. Preferably the hollow microspheres are lime-borosilicate glass microspheres.

Thermal Insulation Application Process The layer or layers of foamed or non-foamed thermal insulation, and any non-foamed protective layer, are applied to the steel tube or a pipe, preferably over the corrosion protection coating or coatings, by side wrapping or cross-extrusion processes, or co-extrusion.

Extrusion can be achieved using single screw extrusion, either in single or joint configuration, or by double screw extrusion methods. In the case of single screw extrusion, the extruder screw may have a single-stage or two-stage design.

A compression screw in a single, stage can be suitable for the extrusion of chemical foam so that the foaming agent is added as a concentrate in the form of pellets or masterbatch that is previously mixed with the polymer to be foamed using a Multi-component blender, for example, mounted on the main feed port of the extruder. The design of the screw is important and can incorporate barrier leakage and mixing of elements to ensure the melting, mixing and transport of the polymer and foaming agent.

With a two-stage screw, the first and second stages are separated by a decompression zone, at which point a physical gas or liquid foam forming agent can be introduced into the molten polymer via an injection port or feed into the barrel extruder The first stage acts to melt and homogenize the polymer, while the second stage acts to disperse the foaming agent, cool the melting temperature and increase the melting pressure before the melt leaves the die. This can also be achieved by joint extrusion, where the two stages are extruders of a single screw effectively individual, the first feed in the second. A two-stage screw is also preferred for the extrusion of polymers that have a tendency to release volatiles when melted, or are hygroscopic, the barrel of the extruder being equipped with a vent port placed on the decompression zone through which the Volatile or moisture can be extracted safely.

Double screw extrusion is preferred when the polymer to be foamed is sensitive to shear stress or if filters or other additives are required to be incorporated in the insulation composition. It is particularly recommended that the extrusion of syntactic foams or blowing foams prepared by the physical injection of a gas or liquid foaming agent. Since the double screw design is usually modular, comprising several separate and interchangeable screw elements, such as mixing and conveying elements, it offers greater versatility with respect to the manufacture of screw profile for optical mixing and melting process.

In the case of syntactic foams, for example, the hollow microspheres are fed directly into the polymer melt using a secondary twin screw feeder downstream of the main polymer feed hopper. An additional consideration with syntactic foams is the potential rupture of the hollow microspheres during extrusion of the foam. The forces of shear and compression within the extruder need to be reduced during the process of the foam to avoid this by the judicious design of the extruders, barrels, manifolds and dice.

A static mixing connection or gear pump can be inserted between the end of the screw and the die to further homogenize the melt, generate fusion pressure and reduce melt flow fluctuations.

For chemical or physical blowing foams, the degree of foaming depends on the required balance of thermal conductivity and compressive strength. A very high degree of foaming, while beneficial for thermal insulation performance, can be detrimental to the compressive strength and drag of the foam. The thermoplastic foams of the present invention are normally foamed from about 5% to about 50%, more preferably 5% to 30% or 10% to 25%. The degree of foaming is defined herein as the degree of rarefaction, that is, the decrease in density and is defined as [(DmatiZ-Despuma) / Dmatriz] X100. Expressed in this way, the degree of foaming reflects the percentage volume of gas under the assumption that the molecular weight of gas is negligibly purchased with that of the matrix, which is generally true. Alternatively, the degree of foaming can be measured visually by microscopic determination of cell density.

With regard to the particular foam insulations present, it is important that the mixing, temperature and pressure conditions are adjusted to give a uniform foam structure comprising very small or microcellular bubbles, in order to ensure the maximum compression strength, thermal performance and resistance to compression drag of the insulation when subjected to high external pressures and pressures. Also when blowing foam insulation is extruded it is important that foaming be avoided until the polymer extrudes from the extrusion die.

The actual coating of the tube can be achieved by using an annular cross die connected to the thermal insulation extruder through which the previously heated tube, with a previously applied corrosion protection layer or multi-layer corrosion protection system, is transported , the thermal insulation that covers the entire surface of the tube in virtue of the annular die that forms the thermal insulation in a tubular profile around the transported tube.

Alternatively, the thermal insulation can be applied by a lateral wrapping technique whereby the thermal insulation is extruded in the form of a sheet or tape which is wrapped around the tube. It may be necessary to apply a number of wraps to achieve the required thermal insulation thickness and, therefore, performance. The individually wrapped layers are fused by virtue of the molten state of the material being extruded. As well it may be necessary to preheat the outer surface of the previous layer to ensure proper adhesion of any subsequent layer.

The application of thermal insulation by the lateral wrapping technique may involve wrapping the tube as it is simultaneously rotated and transported forward along its longitudinal axis, as previously written. This may also involve the application of a pre-extruded tape using heads of rotation while the tube is transported longitudinally but not rotated. In this particular case, the winding angle of the thermal insulation layers can be adjusted by varying the speed of tube movement in the longitudinal direction and / or by varying the rotational speed of the tube or the rotation heads. The tape can be wound in successive layers at opposite winding angles to maintain tube neutrality, until the required thickness has increased. Furthermore, it may be desirable that the applied layers of thermal insulation do not come together and that they can slide over each other with little resistance in order to avoid the rigidity of increasing flexion or dynamic bending.

It is necessary to apply a layer of adhesive between the corrosion protection layer, or system and thermal insulation layer, or between individual thermal insulation layers, this can be achieved by using any sheet of a single layer or annular die, or a die of coextrusion so that a multilayer adhesive or the adhesive in layers of thermal insulation are applied simultaneously. The outer protective top cover, if necessary, can be applied similarly.

Pipe Union Insulation System The pipe joint insulation system referred to in Figure 10 comprises a layer of thermoplastic insulation resistant to high temperatures 13, identical or similar in composition to the layer or layers of thermal insulation and which can be attached to the layer or corrosion protection system 15, the existing thermal insulation layer or layers 6 and the upper cover 7.

The pipe joint insulation system also comprises a corrosion protection layer 15, which may have a single multilayer structure. Preferably, the corrosion protection layer is similar or identical to the corrosion protection layers and systems described above in relation to FIGS. 1 to 4. For example, the corrosion protection layer 15 may comprise the layers of corrosion protection. epoxy and adhesives previously described, applied directly to the welded joint area of the steel tube before application to the layer or layers of thermal insulation.

The tube joint insulation is usually applied by direct extrusion injection into a mold designed to conform to the external dimensions of the insulated tube. The process conditions used will be similar to those used to apply the thermal insulation layer or layers of similar or identical composition.

The tube joint insulation composition can be applied either foamed or as an unfoamed solid.

Eg emplos The present invention is illustrated in the manner of the following examples and with references to Figures 1-10.

Example 1 In this example a steel tube 1 is provided with a three-layer corrosion protection coating as described above in relation to Figure 1, comprising a corrosion protection layer 2, a layer of adhesives 3 and a cover upper 4. The steel tube 1, which was jet treated on its surface and cleaned, had an outer diameter of 140 mm and a wall thickness of 10 mm. Tube 1 was preheated to a temperature of 200 ° C and coated by spraying with a thickness layer of 0.300 +/- 0.100 2 epoxy powder at high temperatures melt bonded (density 1400 +/- 100 g / 1), followed immediately by the extrusion in the top of the epoxy of a layer of 0.300 +/- 0.200 3 of a styrene-maleic anhydride copolymer adhesive modified at high temperatures (density 1.060 g / cm3 and melt flow rate 0.6 g / 10 min) and a cover upper 6.0 +/- 1.0 4 solid poly (ethylene oxide) -polystyrene blend (density 1.060 g / cm3 and melt flow rate 8 g / 10 min) at fusion temperatures of 220 ° C and 260 ° C, respectively. The extrusion of the adhesive layer 3 and top cover 4 was achieved sequentially by extruding the material through the individual sheet dies and wrapping the layers circumferentially around the rotation tube. The tube coated with 3-layer corrosion protection thus produced was cooled to room temperature and tested for the properties shown in Table 2.

Example 2 The corrosion-protected tube produced in Example 1 was further coated with a layer of 20.0 +/- 1.0 mm 6 of the same polyphenylene oxide-polystyrene mixture (degree of foaming = 0%) of the top cover 4 using an extruder equipped with a sheet die preheating the external surface of the tube protected against corrosion at a temperature of about 220 ° C and wrapping the mixture of polyphenylene-polystyrene oxide to a melting temperature of 260 ° C in the outer surface jacket previously heated. The isolated tube thus produced was tested to the properties observed in Table 3.

Example 3 Using the coating procedure described in Example 2, the corrosion protected tube produced in Example 1 was further coated with a layer of 30.0 +/- 1.0 mm 6 of the polyphenylene oxide-polystyrene blend of Example 1 foamed at a density of 0.945 g / cm3 (degree of foaming = 10%) using 0.5% by weight of an endothermic-chemical foaming agent and an outer layer of 5.0 +/- 1.0 mm 7 of polyethylene modified high-impact solid polystyrene (density 1.020 g / cm3 and melt flow index 4.0 g / 10 min). The isolated tube thus produced was tested for the properties observed in Table 3.

Example 4 Using the coating procedure of Example 2, the insulated tube of Example 2 was further coated with a layer of 30.0 +/- 1.0 mm 8 of high impact solid polystyrene (density 1050 g / cm3, degree of foaming 0% e). melting flow index 5.0 g / 10 min) and a outer layer 5.0 +/- 1.0 mm 7 of the polyethylene modified high-impact solid polystyrene of Example 3. The coated tube thus produced was tested for the properties shown in Table 3.

Example 5 Using the coating procedure of Example 2, the insulated tube of Example 2 was further coated with a layer of 30.0 +/- 1.0 mm 8 of the high impact polystyrene of Example 4 foamed at a density of 0.900 g / cm 3 (degree of formation of foam = 15%) using 0.75% by weight of endothermic chemical foaming agent, this foamed layer being further coated with an outer layer of 5.0 +/- 1.0 mm 7 of high impact solid polystyrene of Example 4 modified with styrene-ethylene / butylene-styrene rubber. The coated tube thus produced was tested for the properties observed in Table 3.

Example 6 The tube protected for corrosion produced in the Example 1 but without the styrene-maleic anhydride copolymer adhesive and polyphenylene-polystyrene oxide top cover was coated with a layer of 0.300 +/- 0.200 mm of modified male-maleic anhydride polyolefin adhesive at high temperatures (density 0.950 g / cm3 and melt flow index 1.0 g / 10 min), a 30.0 +/- 1.0 mm 6 layer of solid polypropylene polyphenylene oxide copolymer blend (density 0.970 g / cm3, 0% foam rating and regimen of melt flow 10.6 g / 10 min) and a layer of 30.0 '/ - 1.0 mm 8 of polypropylene copolymers (density 0.902 g / cm3 and melt flow index 0.9 g / 10 min) foamed at a density of 0.750 g / cm3 (degree of foaming = 23%) using 1% by weight of an endothermic chemical foaming agent, this foamed layer being further coated with an outer layer of 5.0 +/- 1.0 mm 7 of the polypropylene copolymers solid. The isolated tube thus produced was tested for the properties observed in Table 3.

Example 7 The corrosion protected tube produced in Example 1 weight without the modified styrene-maleic anhydride copolymer adhesive and polyphenylene oxide-polystyrene oxide top cover was coated with a 0.300 +/- 0.200 mm layer of modified polyolefin adhesive of maleic anhydride at high temperatures (density 0.950 g / cm3, degree of foaming 0% and melt flow index 1.0 g / 10 min), a layer of 30.0 +/- 1.0 mm 6 of the solid polypropylene of Example 6 and a layer of 30.0 +/- 1.0 mm 8 of solid polybutylene (density 0.930 g / cm3, grade of 0% foam formation and melt flow index 0.4 g / 10 min). The isolated tube thus produced was tested for the properties observed in Table 3.

Example 8 The corrosion protected tube produced in Example 1 weight without the top cover of the polyphenylene oxide-polystyrene mixture was further coated with a layer of 20.0 +/- 1.0 mm 6 solid polycarbonate (density 1.190 g / cm3, 0% foam formation and melt flow rate 3.5 g / 10 min (and a layer of 30.0 +/- 1.0 8 of the foamed polycarbonate mima at a density of 1.050 g / cm3 (e-training degree = 12% ) using 0.5% by weight of an endothermic chemical foaming agent, this foamed layer being further coated with an outer layer 5.0 +/- 1.0 mm 7 of solid thermoplastic polyester elastomer (density 1.160 g / cm3 and flow index of fusion 0.5 g / 10 min: The isolated tube thus produced was tested for the properties observed in Table 3.

Example 9 The protected tube for corrosion produced in Example 1 but without the top cover of the polyphenylene-polystyrene oxide mixture was further coated with a layer of 30.0 +/- 1.0 mm 6 of the solid polycarbonate of the Example 8, a 5 mm layer 9 of the modified styrene-maleic anhydride copolymer of Example 1, a layer of 30.0 +/- 1.0 mm 8 of the foamed polypropylene copolymer of Example 6 and an outer layer 5.0 +/- 1.0 mm 7 of the solid polypropylene copolymer of Example 6.

Example 10 Using the coating procedure of Example 2, the isolated tube of Example 3 without the outer layer was further coated with a layer of 30.0 +/- 1.0 mm 8 of the polyphenylene oxide-polystyrene blend of Example 1 foamed at a density of 0.850 g / cm3 (degree of foaming = 20%) using 0.75% by weight of an endothermic chemical foaming agent, this foamed layer being further coated with an outer layer of 5.0 +/- 1.0 mm 7 of the polystyrene of high polyethylene modified solid impact of Example 3. The coated tube thus produced was tested for the properties observed in Table 3.

Example 11 Two 12 m lengths of the tube, protected against corrosion and insulated as described in Example 3, were welded adjoining end to end, the insulating coating having been cut from the steel at the end of each tube to facilitate this process.

After welding the pure metal from the welded area, it was coated with a corrosion protection layer of fusion-bonded epoxy 15 of approximate thickness 0.500 +/- 0.300 mm. The cavity between the epoxy-coated welded joint and the outer diameter of the insulated tube was filled by injecting the polyphenylene-polystyrene oxide mixture of the examples provided at a temperature of about 250 ° C into a circular mold conforming to the outer diameter of the tube isolated. After cooling and removing the mold box, the molded field joint insulation 13 thus produced was tested for the properties observed in Table 4.

Table 2 Table 3 Table 3 (Continued) Table 4

Claims (36)

1. - A high temperature transport conduit insulated for use in the high seas, deep water environments, the conduit comprising: (a) a continuous steel tube formed of one or more tube sections, wherein the steel tube has an outer surface and an inner surface; Y (b) a first layer of thermal insulation provided on the external surface of the steel tube, wherein the first layer of thermal insulation is comprised of a thermoplastic resistant to high temperatures having low thermal conductivity, high smoothing point, high resistance to compression and high resistance to compression drag; wherein the thermoplastic resistant to high temperatures is selected from one or more members of the group comprising: polycarbonate; polyphenylene oxide; polyphenylene oxide mixed with polypropylene, polystyrene or polyamide; polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, or polyetherimide; polyamides, including polyamide 12 and 612 and elastomers thereof; polymethylpentane and mixtures thereof; cyclic olefin copolymers and mixtures of the same; and, partially entangled thermoplastic elastomers, also known as thermoplastic vulcanizers or dynamically vulcanized elastomers.

2. - The insulated transport conduit according to claim 1, wherein the first thermal insulation layer is solid.

3. - The transport conduit according to claim 1, wherein the first thermal insulation layer is a blowing foam or a syntactic foam having a degree of foaming of up to about 50%.

4. - The transport conduit insulated at high temperature according to claim 3, wherein the degree of foaming of the first thermal insulation layer is 5-30%.

5. - The transport conduit isolated at high temperature according to claim 4, wherein the degree of foaming of the first thermal insulation layer is 10-25%.

6. The transport conduit isolated at high temperature according to one or more of the preceding claims, wherein the first thermal insulation layer has one or more of the following properties: high resistance to compression drag at higher temperatures (<7% triaxial); high compression modulus (> 1000 MPa) / high compressive strength (> 25 MPa, uniaxial); : low thermal conductivity (<0.200 W / mK); Long term high temperature support capacity (> 130 ° C).

7. - The high temperature insulated transport conduit according to claim 1, wherein the high temperature resistant thermoplastic is selected from the group comprising polyphenylene oxide and polyphenylene oxide mixed with polypropylene, polystyrene or polyamide.

8. The insulated high temperature transport conduit according to one or more of the preceding claims, wherein the thermoplastic resistant to high temperatures is selected from one or more members of the group comprising: polycarbonate; polyphenylene oxide; polyphenylene oxide mixed with polypropylene, polystyrene or polyamide; polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, or polyetherimide; polyamides, including polyamide 12 and 612 and elastomers thereof; polymethylpentene and mixtures thereof; cyclic olefin copolymers and mixtures thereof; and, partially thermoplastic elastomers interlaced, also known as thermoplastic vulcanizers or dynamically vulcanized elastomers.

9. - High temperature insulated transport conduit according to claim 8, wherein the thermoplastic resistant to high temperatures is selected from the group comprising mixtures of polyphenylene oxide with polystyrene and polyphenylene-polypropylene oxide.

10. The transport pipe insulated at high temperatures according to claim 1, wherein the thermoplastic resistant to high temperatures is selected from the group comprising polycarbonate and polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile acrylate styrene or polyetherimide.

11. - The transport pipe insulated at high temperatures according to one or more of the previous claims, wherein the thermoplastic resistant to high temperatures has a Vicat smoothing point on the scale of 130-200 ° C and a thermal conductivity of 0.15 - 0.20 W / MK.

12. The transport pipe insulated at high temperatures according to one or more of the preceding claims, further comprising a corrosion protection coating applied directly to the external surface of the steel pipe and attached thereto and underlying the first layer of thermal insulation.

13. - The transport conduit insulated at high temperatures according to claim 12, wherein the corrosion protection coating comprises a layer of cured epoxy or modified epoxy.

14. The transport pipe insulated at high temperatures according to claim 12, wherein the corrosion protection coating comprises a phenolic epoxy styrene-maleic anhydride copolymer such as copolymers of styrene-maleic anhydride mixed with acrylonitrile-butadiene- styrene (ABS), polyphenylene sulfide, polyphenylene oxide or poly-imide, including modified versions and mixtures thereof.

15. - The transport conduit isolated at high temperatures according to any of claims 12-14, wherein the first layer of thermal insulation is in direct contact with the corrosion protection coating and adhered directly thereto, the protective coating to corrosion having been treated by discharge of plasma or corona before the application of the first layer of thermal insulation.

16. - The transport conduit isolated at high temperatures according to one or more of the preceding claims, wherein the corrosion protection coating comprises a corrosion protection system multilayer applied to the outer surface of the steel tube and underlying the first layer of thermal insulation, where the multi-layer corrosion protection system comprises: (a) a layer of the cured epoxy or modified epoxy applied directly to the outer surface of the steel tube and attached thereto; Y (b) a first layer of adhesive applied directly to the corrosion protection layer and underlying the first thermal insulation layer.

17. The transport pipe insulated at high temperatures according to claim 16, wherein the adhesive layer is comprised of a polymer provided with functional groups and having a mutual affinity for the corrosion protection layer and the first layer of thermal insulation.

18. - The transport pipe insulated at high temperatures according to any of claims 16 or 17, wherein the first thermal insulation layer is in direct contact with the first layer of adhesives and is bonded thereto.

19. - The transport conduit isolated at high temperatures according to any of claims 16 to 18, wherein the multi-layer corrosion protection system further comprises: (c) a first protective top coating comprised of an unfoamed polymeric material in direct contact with and attached to the first adhesive layer, wherein the thermal insulation layer is in direct contact with the protective top cover and bonded thereto.

20. - The insulated transport conduit according to one or more claims 1-15, wherein the corrosion protection coating comprises a single-layer mixed corrosion protection coating applied directly to the external surface of the steel tube and attached to the same and in direct contact with the first thermal insulation layer, wherein the single layer mixed corrosion protection coating comprises a cured epoxy resin, an adhesive and an unfoamed polymeric material.

21. - The insulated transport conduit according to one or more previous claims, further comprising an outer protective top cover applied on the first thermal insulation layer and forming an external surface of the insulated transport conduit, wherein the outer protective top cover is comprised of of a non-foamed polymeric material.

22. - The transport pipe isolated at high temperatures according to claim 21, wherein the first layer of thermal insulation is in direct contact with the protective top cover and adhered directly to it, the first layer of thermal insulation that has been treated by plasma discharge or corona before the application of the external protective cover.

23. - The insulated transport conduit according to one or more of claims 1 to 21, further comprising a second thermal insulation layer which is comprised of a thermoplastic in the form of a solid, a blowing foam or a syntactic foam.

24. - The insulated transport conduit according to claim 23, wherein the second thermal insulation layer is comprised of a polymeric material that is different from the thermoplastic resistant to high temperatures comprising the first thermal insulation layer.

25. - The insulated transport conduit according to claim 24, wherein the different polymeric material is selected from one or more members of the group comprising: homopolymer or copolymer of solid or foamed polypropylene, polybutylene, polyethylene; polystyrene, high impact polystyrene, modified polystyrene and polypropylene or interlaced or partially interlaced polyethylenes, including copolymers, blends and elastomers thereof; and wherein the first layer of thermal insulation is under the second layer of thermal insulation.

26. The insulated transport conduit according to one or more of claims 23 to 25, wherein the first and second thermal insulation layers are foamed to different degrees.

27. The insulated transport conduit according to claim 26, wherein the first layer of thermal insulation is under the second layer of thermal insulation and wherein the second layer of thermal insulation is foamed to a greater degree than the first layer of insulation thermal.

28. The transport conduit isolated at the temperatures according to one or more of claims 23 to 27, wherein the first thermal insulation layer is under the second thermal insulation layer and is in direct contact with the second thermal insulation layer directly adhered to it, the first layer of thermal insulation having been treated by discharge of plasma or corona before the application of the second layer of thermal insulation.

29. - The insulated transport conduit according to one or more of claims 23 to 27, wherein the first and second thermal insulation layers are separated by a layer of non-foamed polymeric material.

30. - The transport conduit insulated at high temperatures according to claim 29, wherein the inter-layer adhesion is provided between the layer of unfoamed polymeric material and the first and second thermal insulation layers by treating the first thermal insulation layer with plasma or corona discharge prior to the application of the non-foamed polymer material layer and by discharge of plasma or corona from the non-foamed polymer material layer prior to application to the second thermal insulation layer.

31. The insulated transport conduit according to claim 29, wherein the first layer is provided between the layer of unfoamed polymeric material and one or both of the first and second thermal insulation layers.

32. - The insulated transport conduit according to claim 29, wherein the non-foamed polymeric material is an adhesive.

33. - The insulated transport conduit according to one or more of claims 1-20, further comprising a molded pipe union insulation system attached directly to the corrosion protection coating system and first thermal insulation layer in a joint that connects two tube sections.

34. - The insulated transport conduit according to claim 33, wherein the molded tube connection isolation system is comprised of thermoplastic resistant to high temperatures.

35. - A transport conduit insulated at high temperatures for use in deep water environments in the open sea, the conduit comprising: (a) a continuous steel tube formed of two or more tube sections, wherein the steel tube has an outer surface and an inner surface; Y (b) a first thermal insulation layer provided on the external surface of the steel tube wherein the first thermal insulation layer is a solid, a blown foam or a syntactic foam and is comprised of polypropylene; Y (c) a second thermal insulation layer provided on the first thermal insulation layer, wherein the second thermal insulation layer is a solid, a foam blowing a syntactic foam and is comprised of polybutylene.

36. - The transport conduit insulated at high temperatures according to claim 35, wherein both the first and second thermal insulation layers are solid. SUMMARY A polymeric composition to isolate fluid and / or gas transport conduits, so that oil and gas offshore pipelines operate at temperatures of 130 ° C or higher in water depths above 1,000 meters. The outer surface of the duct is provided with at least one layer of solid foam insulation comprising a thermoplastic resistant to high temperatures having low thermal conductivity, high thermal softening point, high compressive strength and high compressive drag. . The thermoplastic resistant to high temperatures are selected from one or more members of the group comprising: polycarbonate; polyphenylene oxide; polyphenylene oxide, mixed with polypropylene, polystyrene or polyamide; polycarbonate mixed with polybutylene terephthalate, polyethylene terephthalate, acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, or polyetherimide; polyamides, including polyamide 12 and 612 and elastomers thereof: polymethylpentene and mixtures thereof; cyclic olefin copolymers and mixtures thereof; and, partially entangled thermoplastic elastomers, also known as thermoplastic vulcanizates and dynamically vulcanized elastomers.